alter table mytest_in_doc split partition p_default at (to_date('01.01.2019', 'dd.mm.yyyy'))
  into (partition p_2018, partition p_default) update indexes;

Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
PL/SQL Release 12.2.0.1.0 - Production
CORE	12.2.0.1.0	Production
TNS for Linux: Version 12.2.0.1.0 - Production
NLSRTL Version 12.2.0.1.0 - Production

--drop table mytest_out_doc;
--drop table mytest_in_doc;
create table mytest_in_doc (
  in_id number
 ,doc_date timestamp default systimestamp not null
 ,cmd varchar2(256) not null
 ,client varchar2(200) 
 ,msg clob
 ,constraint pk_mytest_in_doc primary key (in_id)
)
pctfree 5 pctused 80
lob(msg) store as securefile
partition by range(doc_date) 
  (partition p_2017 values less than (to_date('01.01.2018','dd.mm.yyyy'))
  ,partition p_default values less than (maxvalue)
  );
create index ik_mytest_in_doc$doc_date on mytest_in_doc (doc_date) global partition by range(doc_date)
  (partition p_2017 values less than (to_date('01.01.2018','dd.mm.yyyy'))
  ,partition p_default values less than (maxvalue)
  );

create table mytest_out_doc (
  out_id number
 ,in_id  number not null
 ,doc_date timestamp default systimestamp not null
 ,msg clob
 ,err_code number
 ,constraint pk_mytest_out_doc primary key (out_id)
 ,constraint fk_mytest_out_doc$in_id foreign key (in_id) references mytest_in_doc (in_id)
)
pctfree 5 pctused 80
lob(msg) store as securefile
partition by reference (fk_mytest_out_doc$in_id);
create index ik_mytest_out_doc$in_id on mytest_out_doc (in_id) local;

--1 
create table mytest_in_doc_2;
create table mytest_out_doc_2;
--2
rename table mytest_in_doc to mytest_in_doc_original;
rename table mytest_out_doc to mytest_out_doc_original;
create or replace view mytest_in_doc as select * from mytest_in_doc_2;
create or replace view mytest_out_doc as select * from mytest_out_doc_2;
--3
alter table mytest_in_doc_original split partition p_default at (to_date('01.01.2019', 'dd.mm.yyyy'))
  into (partition p_2018, partition p_default) update indexes;
--4
drop view mytest_in_doc;
drop view mytest_out_doc;
rename table mytest_in_doc_original to mytest_in_doc;
rename table mytest_out_doc_original to mytest_out_doc;
--5
insert into mytest_in_doc select * from mytest_in_doc_2;
insert into mytest_out_doc select * from mytest_out_doc_2;
drop table mytest_out_doc_2;
drop table mytest_in_doc_2;

begin
  dbms_redefinition.can_redef_table(uname => user, tname => 'IN_DOC');
end;
Error report -
ORA-23549: таблица "RUSH"."IN_DOC" используется в эталонном разбиении
ORA-06512: на  "SYS.DBMS_REDEFINITION", line 242
ORA-06512: на  "SYS.DBMS_REDEFINITION", line 5439
ORA-06512: на  line 2

--WITHOUT PARTITION BY REFERENCE------------------------------------------------
create table in_doc2 (
  in_id    number
 ,doc_date timestamp default systimestamp not null
 ,constraint pk_in_doc2 primary key (in_id)
) partition by range(doc_date) (
  partition p_2017 values less than (to_date('01.01.2018','dd.mm.yyyy'))
 ,partition p_default values less than (maxvalue)
);
create table out_doc2 (
  out_id   number
 ,in_id    number not null
 ,constraint pk_out_doc2 primary key (out_id)
 ,constraint fk_out_doc2$in_id foreign key (in_id) references in_doc2 (in_id)
);
create index ik_out_doc2$in_id on out_doc2 (in_id);
begin
  dbms_redefinition.can_redef_table(uname => user, tname => 'IN_DOC2');
end;
/
drop table out_doc2;
drop table in_doc2;

--SCRIPT OUTPUT-----------------------------------------------------------------

Table IN_DOC2 created.

Table OUT_DOC2 created.

Index IK_OUT_DOC2$IN_ID created.

PL/SQL procedure successfully completed.

Table OUT_DOC2 dropped.

Table IN_DOC2 dropped.

--WITH PARTITION BY REFERENCE---------------------------------------------------
create table in_doc3 (
  in_id    number
 ,doc_date timestamp default systimestamp not null
 ,constraint pk_in_doc3 primary key (in_id)
) partition by range(doc_date) (
  partition p_2017 values less than (to_date('01.01.2018','dd.mm.yyyy'))
 ,partition p_default values less than (maxvalue)
);
create table out_doc3 (
  out_id   number
 ,in_id    number not null
 ,constraint pk_out_doc3 primary key (out_id)
 ,constraint fk_out_doc3$in_id foreign key (in_id) references in_doc3 (in_id)
) partition by reference (fk_out_doc3$in_id);
create index ik_out_doc3$in_id on out_doc3 (in_id) local;
begin
  dbms_redefinition.can_redef_table(uname => user, tname => 'IN_DOC3');
end;
/
drop table out_doc3;
drop table in_doc3;

--SCRIPT OUTPUT-----------------------------------------------------------------

Table IN_DOC3 created.

Table OUT_DOC3 created.

Index IK_OUT_DOC3$IN_ID created.

Error starting at line : 17 in command -
begin
  dbms_redefinition.can_redef_table(uname => user, tname => 'IN_DOC3');
end;
Error report -
ORA-23549: таблица "RUSH"."IN_DOC3" используется в эталонном разбиении
ORA-06512: на  "SYS.DBMS_REDEFINITION", line 242
ORA-06512: на  "SYS.DBMS_REDEFINITION", line 5439
ORA-06512: на  line 2

Table OUT_DOC3 dropped.

Table IN_DOC3 dropped.

alter table mytest_in_doc split partition p_default at (to_date('01.01.2019', 'dd.mm.yyyy'))
  into (partition p_2018, partition p_default) update indexes;

--CREATE OBJECTS----------------------------------------------------------------
create table in_doc3 (
  in_id    number
 ,doc_date timestamp default systimestamp not null
 ,constraint pk_in_doc3 primary key (in_id)
) partition by range(doc_date) (
  partition p_2017 values less than (to_date('01.01.2018','dd.mm.yyyy'))
 ,partition p_default values less than (maxvalue)
);
create table out_doc3 (
  out_id   number
 ,in_id    number not null
 ,constraint pk_out_doc3 primary key (out_id)
 ,constraint fk_out_doc3$in_id foreign key (in_id) references in_doc3 (in_id)
) partition by reference (fk_out_doc3$in_id);
create index ik_out_doc3$in_id on out_doc3 (in_id) local;
--INSERT DATA-------------------------------------------------------------------
insert into in_doc3 
select rownum
      ,systimestamp - trunc(500 * dbms_random.value)
  from dual connect by level <= 100;
commit;
insert into out_doc3 
select in_id
      ,in_id
  from in_doc3;
commit;
--ALTER TABLE-------------------------------------------------------------------
alter table in_doc3 split partition for (date'2018-06-01') at (date'2018-06-01'); 
alter table in_doc3 split partition for (date'2018-07-01') at (date'2018-07-01') online update indexes; 
drop table out_doc3 purge;
drop table in_doc3 purge;

--SCRIPT OUTPUT-----------------------------------------------------------------
Table IN_DOC3 created.

Table OUT_DOC3 created.

Index IK_OUT_DOC3$IN_ID created.

100 rows inserted.

Commit complete.

100 rows inserted.

Commit complete.

Table IN_DOC3 altered.

Error starting at line : 30 in command -
alter table in_doc3 split partition for (date'2018-07-01') at (date'2018-07-01') online update indexes
Error report -
SQL Error: ORA-14808: таблица не поддерживает ONLINE SPLIT PARTITION
14808. 00000 -  "ONLINE MOVE PARTITION is not supported for this table"
*Cause:    An ALTER TABLE MOVE PARTITION ONLINE statement was issued on a
           table that was either not a heap table or had an object type,
           domain index or bitmap join index defined on it. This operation is
           only supported for heap tables.
*Action:   Do not use the ONLINE keyword.

Table OUT_DOC3 dropped.

Table IN_DOC3 dropped.